Touch position determining apparatus and method thereof

Abstract

A touch position determining apparatus and method thereof are provided. The touch position determining apparatus is adapted to a sphere. The touch position determining apparatus includes a pressure sensing array and a processing unit. The pressure sensing array is coupled below the sphere and includes a plurality of pressure sensing nodes. The pressure sensing array generates a pressure deformation area in response to a touch operation performed on a surface of the sphere, and generates a pressure signal set by the pressure sensing nodes corresponding to the pressure deformation area. The processing unit is connected to the pressure sensing array and determines a touch position of the touch operation performed on the surface of the sphere according to the pressure signal set.

What is claimed is: 
     
         1 . A touch position determining apparatus, adapted to a sphere, the touch position determining apparatus comprising:
 a pressure sensing array, coupled below the sphere and comprising a plurality of pressure sensing nodes, wherein the pressure sensing array forms a pressure deformation area in response to a touch operation performed on a surface of the sphere, and generates a pressure signal set by the pressure sensing nodes corresponding to the pressure deformation area; and   a processing unit, coupled to the pressure sensing array, and determining a touch position of the touch operation performed on the surface of the sphere according to the pressure signal set.   
     
     
         2 . The touch position determining apparatus as claimed in  claim 1 , wherein the sphere corresponds to a coordinate system, wherein the coordinate system has an origin, an X-axis, a Y-axis and a Z-axis, and the processing unit is configured to:
 calculate a pressure deformation area center point of the pressure deformation area on a X-Y plane and a first azimuth angle of the pressure deformation area center point relative to the X-axis on the X-Y plane according to the pressure signal set, wherein the X-Y plane is defined by the X-axis and the Y-axis;   set an X-coordinate and a Y-coordinate of a pressure center point according to the pressure deformation area center point, wherein the pressure center point is a main pressure point generated by the sphere in the pressure deformation area in response to the touch operation;   calculate a Z-coordinate of the pressure center point according to the X-coordinate and the Y-coordinate of the pressure center point and a sphere radius of the sphere;   calculate a second azimuth angle of the pressure center point relative to the Z-axis according to the X-coordinate, the Y-coordinate and the Z-coordinate of the pressure center point;   correct the pressure center point according to a reference force exerting direction, the first azimuth angle, and the second azimuth angle, wherein the reference force exerting direction is parallel to a force exerting direction of the touch operation, and passes through the origin; and   set a position on the surface of the sphere that is symmetric to the corrected pressure center point relative to the origin as the touch position of the touch operation.   
     
     
         3 . The touch position determining apparatus as claimed in  claim 2 , wherein the processing unit is configured to:
 calculate a first maximum distance between the X-coordinate of the pressure deformation area center point and X-coordinate of a boundary of the pressure deformation area, and a second maximum distance between the Y-coordinate of the pressure deformation area center point and Y-coordinate of the boundary of the pressure deformation area, and set a maximum value of the first maximum distance and the second maximum distance as a specific distance; and   determine whether a pressure deformation area radius of the pressure deformation area is substantially equal to the specific distance, and if yes, set the X-coordinate and the Y-coordinate of the pressure center point according to the pressure deformation area center point.   
     
     
         4 . The touch position determining apparatus as claimed in  claim 2 , wherein the processing unit takes an average value of a maximum value and a minimum value of the X-coordinate of a boundary of the pressure deformation area to serve as the X-coordinate of the pressure deformation area center point;
 the processing unit takes an average value of a maximum value and a minimum value of the Y-coordinate of a boundary of the pressure deformation area to serve as a Y-coordinate of the pressure deformation area center point; and   when the X-coordinate of the pressure deformation area center point is greater than 0, φ A  is tan −1 (Y 2 /X 2 ), and when the X-coordinate of the pressure deformation area center point is not greater than 0, φ A  is 180+ tan −1 (Y 2 /X 2 ), wherein φ A  is the first azimuth angle,   wherein X 2  is the X-coordinate of the pressure deformation area center point, and Y 2  is the Y-coordinate of the pressure deformation area center point.   
     
     
         5 . The touch position determining apparatus as claimed in  claim 3 , wherein when the pressure deformation area radius of the pressure deformation area is substantially not equal to the specific distance, the processing unit sets the X-coordinate and the Y-coordinate of the pressure center point according to the first azimuth angle, the pressure deformation area radius, and a specific pressure sensing node closest to the original in the pressure deformation area. 
     
     
         6 . The touch position determining apparatus as claimed in  claim 5 , wherein when the processing unit sets the pressure center point according to the first azimuth angle, the pressure deformation area radius and the specific pressure sensing node, X A  is (R 2 × cos φ A )+X C , and Y A  is (R 2 × sin φ A )+Y C , wherein X A  is the X-coordinate of the pressure center point, and Y A  is the Y-coordinate of the pressure center point,
 wherein R 2  is the pressure deformation area radius, φ A  is the first azimuth angle, X C  and Y C  are respectively the X-coordinate and the Y-coordinate of the specific pressure sensing node. 
 
     
     
         7 . The touch position determining apparatus as claimed in  claim 2 , further comprising a G-sensor coupled to the sphere and the processing unit, and calculating a first included angle between the reference force exerting direction and the X-axis;
 wherein the processing unit calculates a first correction angle according to the first included angle and the first azimuth angle;   the G-sensor calculates a second included angle between the reference force exerting direction and the X-Y plane;   the processing unit calculates a second correction angle according to the second included angle and the second azimuth angle;   the processing unit respectively corrects the first azimuth angle and the second azimuth angle according to the first correction angle and the second correction angle; and   the processing unit corrects the pressure center point according to the corrected first azimuth angle and the corrected second azimuth angle.   
     
     
         8 . A method for determining a touch position, adapted to a sphere, wherein a pressure sensing array is coupled below the sphere, and the pressure sensing array comprises a plurality of pressure sensing nodes, the method for determining the touch position comprising:
 forming a pressure deformation area by the pressure sensing array in response to a touch operation when the touch operation is performed on a surface of the sphere, and generating a pressure signal set by the pressure sensing nodes corresponding to the pressure deformation area; and   determining the touch position of the touch operation performed on the surface of the sphere according to the pressure signal set.   
     
     
         9 . The method for determining the touch position as claimed in  claim 8 , wherein the sphere corresponds to a coordinate system, the coordinate system has an origin, an X-axis, a Y-axis and a Z-axis, and the step of determining the touch position of the touch operation performed on the surface of the sphere according to the pressure signal set comprises:
 calculating a pressure deformation area center point of the pressure deformation area on a X-Y plane and a first azimuth angle of the pressure deformation area center point relative to the X-axis on the X-Y plane according to the pressure signal set, wherein the X-Y plane is defined by the X-axis and the Y-axis;   setting an X-coordinate and a Y-coordinate of a pressure center point according to the pressure deformation area center point, wherein the pressure center point is a main pressure point generated by the sphere in the pressure deformation area in response to the touch operation;   calculating a Z-coordinate of the pressure center point according to the X-coordinate and the Y-coordinate of the pressure center point and a sphere radius of the sphere;   calculating a second azimuth angle of the pressure center point relative to the Z-axis according to the X-coordinate, the Y-coordinate and the Z-coordinate of the pressure center point;   correcting the pressure center point according to a reference force exerting direction, the first azimuth angle, and the second azimuth angle, wherein the reference force exerting direction is parallel to a force exerting direction of the touch operation, and passes through the origin; and   setting a position on the surface of the sphere that is symmetric to the corrected pressure center point relative to the origin as the touch position of the touch operation.   
     
     
         10 . The method for determining the touch position as claimed in  claim 9 , wherein the step of setting the X-coordinate and the Y-coordinate of the pressure center point according to the pressure deformation area center point comprises:
 calculating a first maximum distance between the X-coordinate of the pressure deformation area center point and X-coordinate of a boundary of the pressure deformation area, and a second maximum distance between the Y-coordinate of the pressure deformation area center point and Y-coordinate of the boundary of the pressure deformation area, and setting a maximum value of the first maximum distance and the second maximum distance as a specific distance; and   determining whether a pressure deformation area radius of the pressure deformation area is substantially equal to the specific distance, and if yes, setting the X-coordinate and the Y-coordinate of the pressure center point according to the pressure deformation area center point, wherein the pressure center point is a main pressure point generated by the sphere in the pressure deformation area in response to the touch operation.   
     
     
         11 . The method for determining the touch position as claimed in  claim 9 , wherein the step of calculating the pressure deformation area center point of the pressure deformation area on the X-Y plane and the first azimuth angle of the pressure deformation area center point relative to the X-axis on the X-Y plane according to the pressure signal set comprises:
 taking an average value of a maximum value and a minimum value of the X-coordinate of a boundary of the pressure deformation area to serve as the X-coordinate of the pressure deformation area center point; and   taking an average value of a maximum value and a minimum value of the Y-coordinate of a boundary of the pressure deformation area to serve as a Y-coordinate of the pressure deformation area center point,   wherein when the X-coordinate of the pressure deformation area center point is greater than 0, φ A  is tan −1 (Y 2 /X 2 ), and when the X-coordinate of the pressure deformation area center point is not greater than 0, φ A  is 180+ tan −1 (Y 2 /X 2 ), wherein φ A  is the first azimuth angle,   wherein X 2  is the X-coordinate of the pressure deformation area center point, and Y 2  is the Y-coordinate of the pressure deformation area center point.   
     
     
         12 . The method for determining the touch position as claimed in  claim 10 , wherein the step of determining whether the pressure deformation area radius of the pressure deformation area is substantially equal to the specific distance, the method further comprises:
 setting the X-coordinate and the Y-coordinate of the pressure center point according to the first azimuth angle, the pressure deformation area radius, and a specific pressure sensing node closest to the original in the pressure deformation area when the pressure deformation area radius of the pressure deformation area is substantially not equal to the specific distance.   
     
     
         13 . The method for determining the touch position as claimed in  claim 12 , wherein the step of setting the X-coordinate and the Y-coordinate of the pressure center point according to the first azimuth angle, the pressure deformation area radius, and the specific pressure sensing node closest to the original in the pressure deformation area comprises:
 when the pressure center point is set according to the first azimuth angle, the pressure deformation area radius and the specific pressure sensing node, X A  is (R 2 × cos φ A )+X C , and Y A  is (R 2 × sin φ A )+Y C , wherein X A  is the X-coordinate of the pressure center point, and Y A  is the Y-coordinate of the pressure center point,   wherein R 2  is the pressure deformation area radius, φ A  is the first azimuth angle, X C  and Y C  are respectively the X-coordinate and the Y-coordinate of the specific pressure sensing node.   
     
     
         14 . The method for determining the touch position as claimed in  claim 9 , wherein the step of correcting the pressure center point according to the reference force exerting direction, the first azimuth angle, and the second azimuth angle comprises:
 calculating a first included angle between the reference force exerting direction and the X-axis through a G-sensor coupled to the sphere;   calculating a first correction angle according to the first included angle and the first azimuth angle;   calculating a second included angle between the reference force exerting direction and the X-Y plane through the G-sensor;   calculating a second correction angle according to the second included angle and the second azimuth angle;   respectively correcting the first azimuth angle and the second azimuth angle according to the first correction angle and the second correction angle; and   correcting the pressure center point according to the corrected first azimuth angle and the corrected second azimuth angle.